1,722,211 research outputs found
Adaptive bit-reduced mean absolute difference criterion for block-matching algorithm and its VLSI design
No full textAn adaptive bit-reduced mean absolute difference (ABRMAD) is presented as a criterion for the block-matching algorithm (BMA) to reduce the complexity of the very large scale integration (VLSI) implementation and to improve the processing time. The ABRMAD uses the lower pixel resolution of the significant bits instead of full-resolution pixel values to estimate the motion vector (MV) by examining the pixels in a block. Simulation results shaw that the 4-bit ABRMAD has competitive mean square error (MSE) results and a half less hardware complexity than the mean absolute difference (MAD) criterion. It has also better characteristics in terms of both MSE performance and hardware complexity than the MiniMax criterion and has better MSE performance than difference pixel counting (DPC), binary block matching with edge map (BBME), and bit-plane matching (BPM) with the same number of bits. (C) 1998 Society of Photo-Optical instrumentation Engineers. [S0091-3286(98)02112-6]
Rotation-, scale-, and translation-invariant image watermark using higher order spectra
No full textDigital watermarks offer means of protecting the copyright of digital multimedia. However, many of the proposed watermarking methods are vulnerable to the geometrical distortions that occur during normal use of the media. We propose a new image watermarking method that is resilient to rotation, scaling, and translation (RST). We use the higher order spectra (HOS), in particular, the bispectrum feature vector of an image as the watermark. The bispectrum is the Fourier spectrum of the triple correlation of a signal. Phases of the integrated bispectra are invariant to translation and scaling. Rotation invariance is achieved using the Radon transform of the image. An image is decomposed into the 1-D projections and we construct a feature vector from them. A watermark is embedded by modifying the vector. We measure the distance between the feature vector extracted from the test image and the watermark at detector. Results of experimental studies show that our method is robust to geometric attacks, JPEG compression, and Gaussian noise. (C) 2003 Society of Photo-Optical Instrumentation Engineers
Web image retrieval using majority-based ranking approach
No full textWeb image retrieval has characteristics different from typical content-based image retrieval; web images have associated textual cues. However, a web image retrieval system often yields undesirable results, because it uses limited text information such as surrounding text, URLs, and image filenames. In this paper, we propose a new approach to retrieval, which uses the image content of retrieved results without relying on assistance from the user. Our basic hypothesis is that more popular images have a higher probability of being the ones that the user wishes to retrieve. According to this hypothesis, we propose a retrieval approach that is based on a majority of the images under consideration. We define four methods for finding the visual features of majority of images; (1) majority-first method, (2) centroid-of-all method, (3) centroid-of-top K method, and (4) centroid-of-largest-cluster method. In addition, we implement a graph/picture classifier for improving the effectiveness of web image retrieval. We evaluate the retrieval effectiveness of both our methods and conventional ones by using precision and recall graphs. Experimental results show that the proposed methods are more effective than conventional keyword-based retrieval methods
An efficient block-matching criterion for motion estimation and its VLSI implementation
No full textThe block-matching motion estimation is the most popular technique for motion compensated coding of image sequence. Due to the intensive computational requirement to perform motion estimation(ME) in real-time, application specific VLSI implementation of the ME is indispensable. In this paper, we present a novel block-matching criterion for motion estimation called Reduced Bits Mean Absolute Difference(RBMAD). By comparison with conventional schemes, our scheme reduces hardware requirement and increases the speed of computation in VLSI chip with acceptable video performance. We describe in details the video performances of proposed criterion and conventional ones. We also show our VLSI implementation using the proposed scheme to compare the hardware requirement and operating speed with conventional ones. It is found that RBMAD using 4bits has reasonable video performance with 57% less VLSI area and 34% faster, thus it is suitable for low cost applications of video coding
Data distribution and alignment scheme for conflict-free memory access in parallel image processing system
No full textIn this paper, we give a solution to the problem of conflict-free access of various slices of data in parallel processor for image processing. Image processing operations require a memory system that permits parallel and conflict-free access of rows, columns, forward diagonals, backward diagonals, and blocks of two-dimensional image array for an arbitrary location. Linear skewing schemes are useful methods for those requirements, but these schemes require complex Euclidean division by prime number. On the contrary, nonlinear skewing schemes such as XOR-schemes have more advantages than the linear ones in address generation, but these schemes allow conflict-free access of some array slices in restricted region. In this paper, we propose a new XOR-scheme which allows conflict-free access of arbitrarily located various slices of data for image processing, with a two-fold the number of memory modules than that of processing elements. Further, we propose an efficient data alignment network which consists of log N + 2-stage multistage interconnection network utilizing Omega network
Re-ranking algorithm using post-retrieval clustering for content-based image retrieval (vol 41, pg 177, 2005)
No full textGoing Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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